The image recording in the instant specification mainly refers to color hard copy recordings such as sublimation transfer, melt transfer, ink-jet printing and electrophotography, and in consideration of dispersibility with dye or pigment, dyeing properties, affinity, etc., polyesters have been used for these image recordings irrespective of recording method. For example, as a dyeable resin for dye-receiving layer of sublimation transfer image receiving paper, there are conventionally known saturated polyesters, as disclosed in U.S. Pat. No. 4,474,859, and Japanese Patent Unexamined Publication Nos. 64899/1985, 258790/1986 and 105689/1987.
When a saturated polyester soluble in organic solvents is used for forming images by sublimation transfer, melt transfer, ink-jet printing or electrophotography, it is possible to obtain high quality images superior in color density, gradation, color reproduction and sharpness, whereas when seen in terms of preservation stability of images against contamination by fingerprints, fats and oils represented by various cosmetics, and plasticizer components in eraser and vinyl chloride sheet, the polyester affected by these components leads to insufficient durability of the images obtained, and particularly, a long-term preservation gives rise to problems of color change, turbulence of images, and the like, failing to meet the requirements with respect to the properties of images.